I'm not certain how best to handle the SQL scripts that need to know where libdir is, but I can think of several
possibilities,one being that "create function" could have a library search path built into it, thus pushing the
knowledgeof where libdir is into some C code (which would probably be getting it from the PGLIB environment variable).
Or we could put the value of libdir into a system table somewhere that the scripts can read at runtime.
The way to handle this is to have rules in the Makefile that do the
substitution. For example, something like the following Makefile
fragment will do the trick, even if the definitition of $libdir in
Makefile.global is modified after configure is run.
SRCDIR=../../.. include ${SRCDIR}/Makefile.global mklang.sql: mklang.sql.in ${SRCDIR}/Makefile.global sed
<$< > $@ -e 's:@libdir@:${libdir}:'
If I remember correctly, this is used in contrib/spi and should be
common practice throughout.
Your suggestion of a single central Makefile.global/config.h to
contain all the configure decisions is a good one. Together with
rules such as above in the various appropriate places, the problems of
variable expansion and post-configure modifications disappear.
Perhaps not for 6.4, though.
Cheers,
Brook
